I do not see on your OP what year the coach is, but between 10/17/2005 and April/ 18/2006 their was a recall on ISL Cummins engines. Serial numbers range from 46543077 to 46603939 the connecting rod contains a machining defect in the wrist pin bushing of the rod that could cause seizure of the piston pin. This could lead to engine failure with the possibility of the rod rupturing the block.
Make sure you do not get stuck with one of these engines, because as I remember Cummins really did not tear the engine up to make sure the wrist pin was not defective, instead they just added a warning light that would tell you if the engine was about to blow up.